Thread bunching up in shuttle

[corkscrew]

I have a Singer 29U171A machine and just got it working good with T-69 thread. I wanted to be able to sew with heavier thread, T135/v-138 bonded nylon and a 24/180 needle. The top thread keeps bunching up in the shuttle. I've checked the timing per my manual and it appears correct. Also have tried adjusting the tension of both the bobbin and top thread feed along with the presser foot settings. No joy. Any ideas what I'm doing wrong? Thanks in advance, Tom

[CowboyBob]

If it bunches underneath it can be either threaded wrong,not enough tension or I've also noticed that the #138 usually only works on large bobbin 29 machines I always recommend #92 as max on a small bobbin.Also if your gears are worn giving the shuttle driver some play it doesn't allow the shuttles to spin all the way forward to release the thread of it.

[corkscrew]

Thanks Bob